The present invention relates to a method of surgical retraction. In particular, the present invention relates to a method of retracting the humerus during shoulder surgery.
Total shoulder replacement (arthroplasty) operations have been performed for many decades to repair shoulder components. These components include the glenoid cavity (socket portion of the shoulder) and the humeral head (ball portion of the shoulder). The shoulder is typically replaced due to a gradual deterioration or wearing of the glenoid cavity and/or the humeral head or ball. Common causes of the deterioration of the shoulder joint from smooth surfaces where the joint is properly articulating to rough surfaces where articulation of the joint is painful include osteoarthritis, Rheumatoid arthritis as well as trauma which injures the shoulder joint. The deterioration causes either the humeral ball, the glenoid cavity or both the humeral ball and the glenoid cavity become rough which results in pain when the shoulder joint is articulated.
Surgical procedures have been the most successful method to alleviate this type of shoulder pain. Either partial or total shoulder replacement surgery can be performed. In a total shoulder replacement procedure, a cup shaped insert, typically manufactured of polyethylene, is inserted into the worn glenoid cavity and a metal ball is used to replace the humeral head. A partial shoulder replacement is performed when either the humeral ball is replaced or the glenoid cavity is repaired with an insert.
The shoulder replacement surgery is conducted by making an incision through the skin into the front of the shoulder. Typically, the incision is about three inches long. Because of the relatively small size of the incision and the surgical site being on one side of the body, access to the surgical site is limited.
After making the incision through the skin, the surgeon divides the tissue and muscle to expose the shoulder joint. When the humeral ball is replaced, the surgeon separates the humeral bone from the humerus, typically with a bone saw. The surgeon has two options when separating the humeral ball from the humerus. The humeral ball may be separated from the humerus while the humeral ball remains within the glenoid cavity. Alternatively, the humeral ball may be dislocated from the glenoid cavity followed by the humeral ball being separated from the humerus.
After separating the humeral ball from the humerus, the arm is retracted away from the body, or laterally. The arm is usually retracted with a hand-held retractor where the surgeon or an assistant must apply a constant force upon the humerus. One hand-held retractor that is used for retracting the humerus is called a Fakuda blade. A Fakuda blade has a flat surface with a curved end. An aperture is disposed within the Fakuda blade which better grips the humerus than a blade having only a flat surface.
After laterally retracting the humerus, the humeral ball is dislocated from the glenoid cavity, thereby exposing the glenoid cavity for insertion of the cup shaped insert. Additionally, laterally retracting the humerus away from the shoulder joint makes the freshly cut portion of the humerus accessible for replacement of the humeral ball.
The humerus is prepared by hollowing a cavity into the interior of the humerus with a rasp to create a place for the humeral ball component to be attached to the humerus. The metal humeral ball includes a stem which is inserted into the hollowed out cavity in the humerus. The metal humeral ball is fixedly attached to the humerus by techniques which are known in the art including, but not limited to, cement or a non-cement technique, such as bony ingrowth.
Typically, at least two strong people are needed to perform a total shoulder replacement. One person is needed to retract the humerus from the glenoid cavity to gain access to both the glenoid cavity and the humerus. The other person is needed to prepare the glenoid cavity and the humerus for the insert and metal ball, respectively. After the replacement components are inserted, the shoulder is reduced (the humeral component is inserted into the glenoid cavity component) to check the angle and fit of the humeral ball into the glenoid cavity insert. If the shoulder components do not adequately fit, the shoulder is again dislocated, the components readjusted, and the humeral ball is positioned in the glenoid cavity . If the stability and placement of the trial inserts is acceptable, the shoulder is dislocated and the humeral implant stem is placed into and secured within the hollowed cavity of the humerus. The humeral ball is again positioned within the glenoid cavity and the stability of the arthroplasty is confirmed.
Due to the multiple dislocations and insertions of the humeral ball into the glenoid cavity, as well as retracting the humerus, the surgical procedure can become quite physically taxing on the surgeon or surgeons performing it. The surgical procedure requires lifting and moving the patient""s arm into multiple positions. At times, the surgeon may need to hold the arm in a selected position for an extended period of time. Depending on the size of the patient, the strenuous activity can lead to fatigue and contribute to surgical error. Additionally, the repeated movement of the arm can cause nerve damage if it is not done precisely and with minimal adjustment. When the surgeon moves the humerus by hand it is common to have continual adjusting occur. Often, the surgeon holding the arm, relaxes or becomes fatigued and allows the arm to move, requiring that the arm be readjusted. The movement can cause the arm to pinch or rub nerves or muscle tissue, possibly causing damage.
The present invention includes a method for performing surgery on a shoulder joint using at least one positionable support arm attached to a retractor support apparatus, where the shoulder joint includes a glenoid cavity, a humerus and a humeral ball attached to the humerus and positioned within the glenoid cavity. The method includes incising a patient to expose the shoulder joint. After exposing the shoulder joint, the humeral ball is dislocated from the glenoid cavity. A retractor is mounted to one of the support arms at a proximal end. A humerus retractor blade at a distal end of the retractor engages the humerus. The humerus retractor blade is positioned about the humerus and a mechanical system within the humerus retractor is manipulated to laterally displace the humeral ball from the glenoid cavity.